text:
When to use beacon, anti-collision, strobe, logo, and navigation lights?
During taxi, the taxi lights are used, and I think the landing lights are required to be used up to 10.000 feet for all commercial flights.
However, my question is regarding the abovementioned lights: beacon, anti-collision, strobe, logo, and navigation lights. When are they to be used, and when should they not be used? What is the meaning and purpose of each one?

The Aeronautical Information Manual (AIM) is a great place to look for questions like this, and has this on the subject:

4-3-23. Use of Aircraft Lights
a. Aircraft position lights are required to be lighted on aircraft
  operated on the surface and in flight from sunset to sunrise. In
  addition, aircraft equipped with an anti-collision light system are
  required to operate that light system during all types of operations
  (day and night). However, during any adverse meteorological
  conditions, the pilot-in-command may determine that the anti-collision
  lights should be turned off when their light output would constitute a
  hazard to safety (14 CFR Section 91.209). Supplementary strobe lights
  should be turned off on the ground when they adversely affect ground
  personnel or other pilots, and in flight when there are adverse
  reflection from clouds.
b. An aircraft anti-collision light system can use one or more
  rotating beacons and/or strobe lights, be colored either red or white,
  and have different (higher than minimum) intensities when compared to
  other aircraft. Many aircraft have both a rotating beacon and a strobe
  light system.
c. The FAA has a voluntary pilot safety program, Operation Lights On,
  to enhance the see-and-avoid concept. Pilots are encouraged to turn on
  their landing lights during takeoff; i.e., either after takeoff
  clearance has been received or when beginning takeoff roll. Pilots are
  further encouraged to turn on their landing lights when operating
  below 10,000 feet, day or night, especially when operating within 10
  miles of any airport, or in conditions of reduced visibility and in
  areas where flocks of birds may be expected, i.e., coastal areas, lake
  areas, around refuse dumps, etc. Although turning on aircraft lights
  does enhance the see-and-avoid concept, pilots should not become
  complacent about keeping a sharp lookout for other aircraft. Not all
  aircraft are equipped with lights and some pilots may not have their
  lights turned on. Aircraft manufacturer's recommendations for
  operation of landing lights and electrical systems should be observed.
d. Prop and jet blast forces generated by large aircraft have
  overturned or damaged several smaller aircraft taxiing behind them. To
  avoid similar results, and in the interest of preventing upsets and
  injuries to ground personnel from such forces, the FAA recommends that
  air carriers and commercial operators turn on their rotating beacons
  anytime their aircraft engines are in operation. General aviation
  pilots using rotating beacon equipped aircraft are also encouraged to
  participate in this program which is designed to alert others to the
  potential hazard. Since this is a voluntary program, exercise caution
  and do not rely solely on the rotating beacon as an indication that
  aircraft engines are in operation.
e. Prior to commencing taxi, it is recommended to turn on navigation,
  position, anticollision, and logo lights (if equipped). To signal
  intent to other pilots, consider turning on the taxi light when the
  aircraft is moving or intending to move on the ground, and turning it
  off when stopped or yielding to other ground traffic. Strobe lights
  should not be illuminated during taxi if they will adversely affect
  the vision of other pilots or ground personnel.
f. At the discretion of the pilotincommand, all exterior lights
  should be illuminated when taxiing on or across any runway. This
  increases the conspicuousness of the aircraft to controllers and other
  pilots approaching to land, taxiing, or crossing the runway. Pilots
  should comply with any equipment operating limitations and consider
  the effects of landing and strobe lights on other aircraft in their
  vicinity.
g. When entering the departure runway for takeoff or to “line up and
  wait,” all lights, except for landing lights, should be illuminated to
  make the aircraft conspicuous to ATC and other aircraft on approach.
  Landing lights should be turned on when takeoff clearance is received
  or when commencing takeoff roll at an airport without an operating
  control tower.

Here are some types of lights:

A beacon is a light that flashes slowly.
Strobes are the bright white lights that flash about once per second.
Navigation lights are the red, green, and white lights that are on continuously, like on a boat.
Logo lights are lights used to light up something on the side of the plane, and their use is optional.

Strobes and beacons are considered anti-collision lights.
Anti-collision lights, if the plane has them, should be used whenever the engine is running except when they interfere with ground operations. Strobes do not have to be used all the time if a beacon is on.
Navigation lights should be used during night operations.

Where a beacon is present, general practice (and according to Lnafziger's quote from the AIM, FAA recommendation) seems to be to turn off strobes when on the ground and not on a runway.

Would it be correct to say that logo lights are a sort of vanity thing for airlines, and don't have any sort of safety purpose? As such, is there any condition under which they are required to be extinguished - when their light might contribute to a safety issue?

@AnthonyX It can be helpful for air traffic controllers and other pilots to be able to see the logos on other aircraft for identification purposes. This helps to prevent confusing one aircraft with another (though it may be less helpful as a distinguishing factor in an airport like Atlanta where there are 200 aircraft on the ground and 180 of them are painted in Delta livery.) Logo lights are generally aimed at your own aircraft, so it would be unusual for them to pose a safety issue. Also, see Ralph's answer regarding visibility.

Specifically on Logo Lights:
They're useless during the day, but they make the aircraft much easier to see from the side at night, both when taxiing and in flight.  Different carriers will have different rules; one such rule is at night + below 18,000': logo light on.  Above 18,000' and/or during the day, logo light off.
Perhaps the greatest benefit to the Logo Light is when crossing a runway -- gives dramatically more lit-up surface for somebody at the 3 or 9 o'clock position to see (i.e. the pilot who is on the runway that you're crossing).
That, and it's nice marketing to see all your company's aircraft sitting next to each other at their gates, tails all lit up & looking pretty!

FARs are available online here.
91.205 says for night flight, you need position lights (the red, green, white lights), anti-collision lights, and a landing light if flown for hire.
IIRC, it is customary, but not required, to activate the flashing red beacon any time the engine is running, as a warning to people on the ground. This might be mentioned in the AIM, but I'm pretty sure it's not in the FARs.

I just read a comment by an FAA official (who's titles include CFII, where she recommends that the rotating beacon power switch always be left in the ON position, as that can be a helpful totemic reminder that you've inadvertently left your planes master switch on after tie down.

In addition to the FAR and AIM, most commercial operators (and savvy private operators) follow guidance in Advisory Circulars.  These are voluntary procedures that describe recommendations on best practices to stay legal and safe.
Since you specifically mention commercial operations, AC 120-74b is worth a read.  It applies only to taxi procedures but there are hundreds of other ACs about all kinds of topics.  Beginning on page 11 there are several pages about lights on the ground:

(a) Engines Running. Turn on the rotating beacon whenever an engine is running.
(b) Taxiing. Prior to commencing taxi, turn on navigation, position, anti-collision, and logo lights, if available. To signal intent to other pilots, turn on the taxi light when the aircraft is moving or intending to move on the ground, and turn it off when stopped or yielding or as a consideration to other pilots or ground personnel. Strobe lights should not be illuminated during taxi if they will adversely affect the vision of other pilots or ground personnel.
(c) Crossing a Runway. All exterior lights should be illuminated when crossing a runway.

There is a corresponding AC created toward flight training and single pilot ops as well.


text:
What is the length of an A380 aileron?
I work as a paint shop prepper at an airport in the UK and have currently worked on a aileron of a 757-200 that was 14ft long and wanted to compare it to that of a A380

Can you be a little more descriptive as to what you are looking for please?  Specs for the A380 are easily found through google so it is unclear to me what you wish to know.

A good source of public information is the aircraft characteristics document that the manufacturers typically publish for each model, including the A380.
A scale planform drawing can be found on page 310 of the PDF, subject 8-0-0. Based on this drawing, the rough size of the ailerons can be estimated.
The aileron is divided into three sections which move independently (see Why do some aircraft have multiple ailerons per wing?). The outboard section is about 4m (13 ft) long, the middle section is about 3m (10 ft) long, and the inboard section is about 2m (6.5 ft) long. In total they are about 9m (29.5 ft) long.
Derived from Airbus document:

Ailerons viewed from cabin:

Image source (other question)

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text:
What is the procedure to contact EASA to evaluate the certifiability of a system?
I work in academia, and often we are "accused" of living in an ivory tower with no connections to the real world.
To reduce the gap between academia and this "real world" I've heard about, I would like to involve EASA in the research project I am currently involved in.
What is the correct procedure to do this?
For clarity:

it would be only about software
it is not something covered by DO-178C/equivalents (I have problems/questions about the high-level requirements, that are an input for the procedures in DO-178)
it is a program running on a machine with a real-time operating system (RTOS) on board the aircraft. Currently we have no plans concerning maintenance cycles, so I would not be able to say if it could go on a easily exchangeable module (but my guess is no).

Are you trying to determine if it is certifiable, or is it similar to an already certified system? Are you looking to include software or complex hardware (FPGAs, PLDs)?

@selectstriker2 In theory I know it is not even remotely certifiable as of now, and I would like to work with them on how to make it certifiable. Software only. Note that this is not a DO-178 issue.

Are you looking at software embedded within a device/LRU or just the software program (such as one that would run in an RTOS)?

You say that it isn't covered by DO-178C, am I correct in assuming this doesn't actually go in/on the airplane?

@selectstriker2 (thanks for the questions!) currently I have no experience with LRUs, but from a brief look, I would guess it would not be compatible with such a strategy, so I have to say just the program, running on a machine with a RTOS. It goes in the airplane, but DO-178 covers the programming side, I have problems with the high level requirements.

This might sound stupid, but did you try their official contact page? There should be a process that will bring you into contact with the proper person on the other side. In the end, you will not deal with EASA but a specific representative who is responsible for your request. Worked well for me most of the time.

@PeterKämpf no, I did not yet try that, I first wanted to see if there was a specific channel available, but it seems to be the way to go for this specific situation.

Have you considered an industrial partnership with a company who are involved in the development of software for an aircraft application. They might be willing to partner with your university and talk you through the finer points. As selectstriker2 as already said, you can't get away from DO-178 if you are developing software for an airborne application but depending on the criticality of your application, not all of its objectives may apply to you.

@scotty3785 as I said previously my questions are not about development, DO178 does not apply to my questions. and no company would waste their time on something so untested.

@Federico then EASA are unlikely to speak to you either. They are incredibly busy and those in the industry have to book time with EASA reps months in advance. Perhaps you should ask your questions on here and those with appropriate experience might be able to help you. I'll keep an eye out for your question to see if I can help.

@scotty3785 I appreciate the intention, but aviation.se in not a scientifically citable source.

@Federico It isn't but if you actually ask the question, the best answers will come with references to citable sources.

@scotty3785 I don't know how to explain myself, I'll try one last time: the source can only be EASA, it is something never done before (or it would not be an academic project) hence there is nothing online or elsewhere that can answer me

@Federico Good luck in contacting EASA then.

@Federico, Is the software controlling any part of the aircraft or providing real time data to the flight crew, or is it more of a flight data collection and analysis software?

@selectstriker2 the first one you said (control over the aircraft). The thing is that I know how DO178 works, and I understand what are the procedure to follow it, but I need to know if my assumptions on the high level requirements are realistic or not.

@Federico, and what assumptions are those? Or are you referring to specific HLSW requirements for your project?

@selectstriker2 something that is specific to the project, yes.

DO-178 / ED-12C
Any software that executes on installed hardware in a type certified aircraft will need go to through DO-178C (or a similar process). The amount of effort involved depends on the safety criticality of the software functions.
Since this sounds like a new system without predefined System Requirements (such as those you would get from an OEM as part of the SAE ARP 4754A processes), those will need to be defined by your development process and then your Software (High Level) Requirements trace from those.
Here in the US, smaller companies will typically contact and work with the local ACO (Aircraft Certification Office) during the product planning stages to identify the product as following the DO-178C processes.
Larger companies, especially OEMs, tend to work with DERs (Designated Engineering Representatives) rather than directly with the ACO, as they may have dozens of different DO-178 projects going at one time.
EASA Software Certification
Guidance on the EASA Software Aspects of Certification can be found in EASA CM -SWCEH - 002 PDF
From that document, Panel 10 seems to be the part of EASA that you would work with, although I haven't found how a new applicant would go about contacting them yet.

The EASA panel in charge of software and AEH aspects of certification.
  This panel includes at least one software and AEH expert (who is the
  coordinator) and, depending on the size of the project, may include
  additional software and AEH experts.

There is also a FAQ page for the application processes with EASA:
https://www.easa.europa.eu/the-agency/faqs/application-process

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text:
At what distance beyond the aiming point is a landing considered a "Deep Landing"?
In Flight Data Monitoring (FDM) programmes, the Deep Landing calculation is based on difference between the aim point (or glide slope touchdown point) and the actual touchdown point.
How are the limit values for determining whether a landing qualifies as a Deep Landing specified for long or short runways?
Is there a legal distance after which a landing is qualified as "deep". Does that depend on the runway length?

Related

I believe that needs to be decided by the operator, taking into account their operation and fleets. For a jet on a short, normally wet runway, I would allow for a smaller margin than for a turboprop onto 4000m dry asphalt.
In the absence of any other information, maybe a sensible starting point could also be to look at what assumptions have gone into crew‘s landing performance calculations. On large jets, nowadays often a 7 second (or 1500ft) air distance is assumed between crossing the threshold and touchdown, in line with TALPA ARC recommendations. An air distance longer than that will invalidate the performance calculations (as this value is assumed to contain some margin already, using the full 1500ft will already use up all margin on the air part of the landing) and would thus provide a sensible event threshold. Obviously this would have to be reconciled against runway aiming point markings etc. in the FDM event validation to prevent a non-standard runway marking from generating false positives.

+1 for "decided by the operator". Setting the flag at a touchdown 1501' past the threshold would get a lot of flags raised for landings that are probably perfectly safe and not really egregious. Setting the flag for 3000' would probably narrow things down to a smaller data set of more "interesting" (i.e. troubling) occurrences. It all depends on what the analyst is interested in capturing.


text:
Gyro Erection System
I have a hard time understanding the physics behind the pneumatic erecting system in an attitude indicator. According to my book and the linked image, the applied force is “precessed 90 degrees” (anti-clockwise seen from above) and thus re-aligns the gyro. I understand how the pendulous vanes change the exhaust of the air, but since this part is stationary, i.e. not rotating, how can the net force be precessed?

https://savageplane.files.wordpress.com/2017/06/pendulous-vanes-figure-10-101-screenshot-from-2017-06-06-171632.png

Gyroscopes have two types of motion.
The gyroscope spins within its housing (usually at a pretty high speed).
The housing can change attitude within some limits.
The vanes aren't part of spinning gyroscope, but they are part of the housing (which can shift/rotate with respect to the airframe).  The vanes create a torque to change the attitude of the housing.
There is a youtube video with some animations that try to show this effect.

Thank you. That’s a nice video, yet I still have trouble seeing how the gyroscope moves the force 90 degrees since the housing only can tilt. It seems like the force should remain where it is.

The housing can pitch inside the fork, and the fork (which is pretty light) can roll.  So   forces that try to pitch or roll the housing will cause it to move in either of those two axes.

Okay. I think my understanding of gyroscopic precession wasn’t up to date, so I’ve looked some more into that.

Precession (roll force but yaw movement): https://youtu.be/XPUuF_dECVI?t=2167

The pendulous vanes do move around the hinge at the top. And it stays vertically aligned due to gravity, that’s why when the gyro is moved, a vent closes and another will be opened.

Okay. It kind of makes sense that they should rotate with the gyro. Thanks!

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text:
What principle does the attitude indicator in the G1000 use?
The heading indicator in the G1000 uses a magnetometor, but how can the attitude indicator work in the G1000?
Does it work with a tilt sensor, rate sensor or accelerometer?

G1000 is a multi-unit system. The attitude information comes from a specialised unit called AHRS (Attitude and Heading Reference System), typically GRS 77. AHRS uses two solid-state gyros (vertical and directional), plus a magnetometer, to obtain a complete attitude information.
In addition, AHRS does employ accelerometers and rate gyros. Their data is used for stabilisation, filtering, and as an input for autopilot and other systems.

"AHRS uses two solid-state gyros (vertical and directional)" - Does this mean that the AHRS uses gyros to sense the pitch rate and roll rate, but not the yaw rate?

A gyro, whether attitude (angle) or rate one, can (technically) measure two out of three angles. So in fact they have an overlap.

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text:
What is required to 'upgrade' software from DAL C to DAL A?
What are the things to be noted or considered if a software which was initially treated as DAL C and later wanted to be considered as DAL A?

Read DO-178C and look for the different requirements between level A and C.

This question is understood by software developers familiar with certification requirements.

The main difference in effort is in the amount of verification required.
Design Assurance Level (DAL) C only requires statement coverage whereas DAL A requires MC/DC coverage.
Some of the DO-178C objectives have to be meet with independence where they didn't need to be previously, and some life cycle data goes from CC2 to CC1.
I would suggest looking at the objective tables A1-A10 in DO-178C


text:
Inconsistent ARINC 717 Barker Codes
I've been trying to decode a file that is (supposedly) ARINC 717. According to all the literature I've been able to find on ARINC 717, the data should be separated into 4 repeating, one second frames, the start of which is delineated by a frame start code or 'barker' code. According to the literature, these codes should be 001001000111,  010110111000, 101001000111 and 110110111000.
I would therefore assume that these codes should appear an approximately equal number of times throughout the file, but this is not true. I've constructed a code to iterate through each combination of bits and log the number of times these codes occur, and the results generally show that the 1st and 4th codes appear a large number of times (thousands to tens of thousands), but the second and third codes only appear a handful of times (tens to hundreds). This seems very inconsistent with the literature of ARINC 717. I have tried these codes most and least significant bit first. I have assumed therefore that the data had been processed in some additional way, be it encryption or compression, but I'm at a bit of a loss.
Are these codes correct, and is there a gap in my logic?

Providing a small, relevant sample of the data would make this far less of a shot in the dark.

@AdityaSharma I’m not sure if you’re familiar with ARINC, it is both the aviation electronics standards body, and simultaneously a private company.  Devices in the aircraft use ARINC protocols as the way they communicate with each other, and to communicate with ground services.  There’s over 100 different ARINC standards and 717 establishes the data format for flight data recording.  See https://en.m.wikipedia.org/wiki/ARINC.  I believe that the reason the OP didn’t provide more context is that it’s a question that can’t be answered without the person already having ARINC expertise.

@MaxR Alright, sure

This is correct. I also can't provide a sample of the data for commercial reasons, apologies.

Barker codes are used for frame synchronization, due to their strong autocorrelation property, along with error correction codes. They are in the frame preamble, not part of data, therefore you may not be able to see them in the frame data.

After consultation with a third part organisation, I've discovered that the issue here was that there was an additional layer of proprietary encoding above the Arinc 717 that rendered this approach useless without information on this additional encoding scheme.
I hope this helps someone in a similar situation.


text:
What is the fuel burn rate for climb of a C-130J Hercules?
I am trying to graph the payload range for a C-130J Hercules and I need an approximate value for fuel burn rate which I cannot seem to find online. Does anyone know approximately how much fuel a C-130J hercules would burn to climb 1000 ft?
This would be under atmospheric conditions and at standard speeds. The fuel burn rate of any other similar aircrafts is also appreciated. I am just looking for an educated estimation.

A rough estimation: for a mass of 60000 kg, the energy needed for that (1000 ft = 305 m) altitude change will be 60000 x 9,8 x 305 = 179 MJ. Jet fuel has a heating value of 44 MJ/kg, and if we assume a global conversion efficiency of –say– 7%, the fuel needed would be 179/(44 x 0,07) = 58 kg...

That's a great way of looking at it, thanks so much!


text:
How long is a METAR valid for after issuance?
I was wondering how long is the METAR report valid for after issuance? I know some airports issue them every 30 minutes and some every hour. So I wanted to know if a METAR is issued at 8:30AM then will it be valid till next Metar report i.e. 9:00AM or is it just valid for 10-15 minutes after that ?

What does "valid" mean in this context? It's an historical report of what the weather was at the time of issue. Metar reports are typically issued at about :53 past each hour, and also when conditions change "enough" to require one (i.e. a change from 8,000 SCT to 6,000 SCT might not warrant a new one, while 2,000 SCT to 1,000 BKN probably would). But the old one isn't invalidated; it's still out there to reference for trend information: it's just no longer the most recent one.

About one minute, practically speaking.  I've found then useful only when aggregated with METARS from other areas at about the same time -or- for identifying a trend over a few hours.  The question they answer is: "what can  I generally expect to see at this airport when I arrive in about an hour or two?"  Big weather events throw that out the window though.

Typically they are "valid until the next one is issued". Large weather events may mean that there is a METAR issued between regularly scheduled ones. METAR's are really only valid for flight planning purposes, once you are in the air you should rely on ATIS, NEXRAD, and other in-flight services.

Thanks for your answers !

Related

A METAR is a report of conditions at a specific time, so it's only valid when it's issued. It's not a forecast, the weather could be different 5 minutes later. TAFs are forecasts that have a time range, they are valid during that time range. That doesn't mean they are guaranteed to be correct, it's just a prediction.

This is correct.  Metars are typically issued once an hour at the 55 minute mark.  The metar can be issued more frequently is weather changes from the previous metar or if a correction is made to a previous metar.


text:
What medical history questions are asked for a UK Class 1 Medical?
For anyone who has been through a Class 1 medical in the UK, when they run through your medical history what sort of questions are they asking?

In the general medical examination they will go through the medical history you have written in FORM MED 160.

Ok thanks. And where is the bar in terms of when to tick yes to a question on the medical history? i.e. do they want to know about every GP visit you've ever had, or only positive diagnoses?

@Bill The form clearly asks if you have ever had specific medical conditions, not about routine GP visits.

You need to fill in the form according to the instructions written in the last page. In doubt, you can ask or clarify on the day of the examination

I could not find information on specific questions but ICAO Annex 1 (to which the UK adheres) states that:
An applicant for any class of Medical Assessment shall be required to be free from:
a) any abnormality, congenital or acquired; or
b) any active, latent, acute or chronic disability; or
c) any wound, injury or sequelae from operation; or
d) any effect or side-effect of any prescribed or non-prescribed therapeutic, diagnostic or preventive medication taken;
such as would entail a degree of functional incapacity which is likely to interfere with the safe operation of an aircraft or with the safe performance of duties.
There is also a note that says that use of herbal medication and alternative treatment modalities requires particular attention to possible side-effects.
The questions may be formulated in such a way as to meet these requirements.


text:
How long it takes for Pilots to prepare for landing?
I'm wondering how many minutes prior to Final approach do pilots decide what type of approach they will carry on with at the arrival airport like (VISUAL/CATI,II,IIIA,IIIB) ?
Like how many minutes before they get the latest METAR or weather reports and decide accordingly how to carry on with their final landing and how long all this preparation takes before the actual touchdown ?

I added the airline-operations tag because I think you're asking about airline pilots preparing for arrival. A single pilot in a light aircraft could be quite different.


text:
Do I need to be 'current' or hold a medical to become a Basic Ground Instructor?
I want to become an aviation ground instructor BGI.
I hold a commercial, multi, instrument and F/E pilot certificate but haven’t flown in a long time.

Do I need to be “ current” to become a BGI?
Do I need an FAA medical?

You do not need a medical certificate.  It also does not matter that you have not flown in a long time.  You will need to study and take two separate tests to get you ground instructor certificate.

Fundamentals of Instruction (FOI) Test
Ground Instructor Test

The FOI information is covered extensively in the Aviation Instructor Handbook and is 50 questions (at least it once was).
The Flight Instructor test question bank is also used for the BGI (Basic Ground Instructor) and AGI (Advanced Ground Instructor) tests.  If I remember correctly, the BGI test is 80 questions and the AGI test is 100 questions.  The information on the test is covered in multiple FAA handbooks (not all inclusive):

Pilots Handbook of Aeronautical Knowledge
Airplane Flying Handbook
Rotorcraft Flying Handbook
Balloon Flying Handbook
Aviation Weather Services

One thing to notice is that the ground instructor test covers all aircraft and not just the "airplane category" as you can teach and sign off written tests for all aircraft.  Since the BGI and the AGI are the same test, I would suggest getting an AGI as you will be able to sign off all written tests and not just tests for sport, recreational or private pilots.

Your answer is greatly appreciated.

Make sure to check out FAR Title 14, Chapter 1, Subchapter D, Part 61, Subpart 1, §61.215-§61.217.
To be eligible for a ground instructor certificate you must:
(1) Be at least 18
(2) Be able to read, write, speak, and understand English
(3) Pass a knowledge test on instruction (not necessary if you are already a CFI, hold a 7th grade or higher teaching certificate, or work as an accredited teacher at a college or university.
(4) Pass a knowledge test on aeronautical knowledge.
Once you have the rating, to act as a basic ground instructor, one of these things must occur during the preceding 12 calendar months to be considered “current”:
(a) Employment or activity as a ground instructor giving pilot, flight instructor, or ground instructor training
(b) Employment or activity as a flight instructor giving pilot, flight instructor, or ground instructor ground or flight training
(c) Completion of an approved flight instructor refresher course and receipt of a graduation certificate for that course
(d) Receive an endorsement from an authorized instructor certifying that the person has demonstrated knowledge in the appropriate subject areas.
No medical is required.


text:
Does the FAA always require a neuropsychological assessment battery for applicants with a history of ADD?
I'm in the middle of a medical struggle with the FAA. I'm applying for a 3rd class medical certificate but was hit with a deferral letter due to a childhood ADD diagnosis. Currently the FAA is only asking for:

"A personal statement regarding my ADD history and medication use."
"All treatment records and evaluation from the physician who prescribed the ADD medications in the past."

My question is this - does the FAA require a neuropsychological battery test for all applicants with an ADD history, or is their requesting a testing battery contingent upon what I say in my personal statement and the included treatment records / evaluations?
My treatment records and physician evaluation conclude that I no longer have ADD symptoms. In addition, I've flown intensively with a United Airlines check airman (pilot responsible for evaluating the flight ability of other United Airline pilots) and he has written a letter stating he's seen no evidence of ADD and, in his professional opinion, I am qualified to pilot an airplane.
Do you think, after submitting this documents in my favor, I will be able to avoid undergoing the testing battery?

"...is their requesting a testing battery contingent upon what I say in my personal statement..." A clue, Sherlock. I get the feeling you broke the cardinal rule of dealing with FAA Aeromedical -- never, ever tell them what they don't need to know.

Hi Juan - I'm a little confused about your response. Are you saying that their requesting a battery is or is not dependent on what I ultimately submit in my personal statement. I didn't break the "cardinal rule" because I haven't told them anything yet....

This: "...because I haven't told them anything yet.." is the opposite of this "I'm in the middle of a medical struggle with the FAA." Hmm. Anyway, ask your AME what to put in the statement. If the AME has no experience dealing with applicants with past history of ADD, find a different AME who does. Contact AOPA as well for additional guidance. If you are not a member, become one now. You will likely need that help.

Ask an AME, not an internet message board. That's the answer to nearly every question on here about "I have ___, can I get a medical". We aren't AME's, and what happened to this or that poster or 'somebody I knew who had ___' isn't all that relevant unless all the details of their case match yours. Answers to questions that a non-AME wouldn't know to ask you can make a big difference. Get authoritative answers from an experienced flight doc; there is nothing more than that which we can tell you about your medical case that's worth the electrons it's written on.

Different question, but the answer applies verbatim: https://aviation.stackexchange.com/a/27346/7532

I'll bet your original childhood diagnosis was bogus, and you were just a high energy, fidgety kid.  This is a crisis in my view.  My mother used to constantly get on my case (in a light hearted way) of me picking things up to examine them ("you're always fidgeting with things!"). I'm lucky that this was the mid 60s and not the mid 90s, or i probably would have been labelled an ADHD case. And I'm still constantly fidgeting with things...

If you have ever in your life been diagnosed with any mental health condition, such as ADD/ADHD, then the FAA presumes you to be mentally defective until proven otherwise to their satisfaction, by their own experts at your expense. They do not care what your personal doctor says, or what other pilots say.
You will need to get evaluations from a HIMS Psychiatrist and/or HIMS Neuropsychologist, which will likely take you months to arrange since there are only a few in the entire country. Then you will need a HIMS AME to process the paperwork and send it to OKC, which will spend a few months reviewing it to make sure the file is complete. Then your file will be sent to DC, where it will sit on the Federal Air Surgeon’s desk for several more months before he reviews your file. If all goes well, he will issue a Special Issuance medical, conditional on renewing the above evaluations every 6 or 12 months until he is eventually convinced you are mentally stable enough for a regular medical certificate. That may take up to 10 years, depending on your exact condition.
If your AME is not a HIMS AME, they will have no idea how this process works or what paperwork is required, so switch now and save yourself months of wasted time and money.

That kind of uphill climb would be enough to motivate me to stick to Part 103.

@JohnK Or a motorglider. No medical needed, period. Interesting bit of trivia: The FAA regs do not specify any requirements to classify an aircraft as an experimental amateur-build motorglider. Think about that for a sec.

@JohnK It’s a contributing factor to the (pre-COVID) US pilot shortage given how many people under ~35 were misdiagnosed as ADD/ADHD. But the new Federal Air Surgeon (Jan 2021) has claimed she will fix this process. I hope in a year or two I can edit this answer...


text:
When would a pilot request a "VMC descent" or "VMC climb"?
Can anybody explain what's the point of this and in what kind of situations a pilot needs it?
ICAO Doc 9432 "Manual of Radiotelephony"

8.3.3 An aircraft may request a clearance to climb or descend maintaining own separation while in VMC, in daylight, below 10 000 feet in airspace classes D and E. The clearance shall include information on essential traffic.
Example:
P: FASTAIR 345, REQUEST VMC DESCENT TO FL 60
C: FASTAIR 345, DESCEND TO FL 60, MAINTAIN OWN SEPARATION AND VMC FROM FL 90 TO FL 70, TRAFFIC WESTBOUND FRIENDSHIP FL 80, ESTIMATING WICKEN VOR AT 07.

Possibly related, but US-specific

@Pondlife No, that is something completely different

It would be needed when otherwise the flight path would not be cleared because ATC cannot ensure separation with the conflicting traffic. The pilot agreeing to maintain their own separation in VMC allows the level change to be cleared despite the conflicting traffic.

In the case of a VMC descent, this frequent request by pilots prevents them from having to be vectored for a formal ILS approach which may otherwise take them many miles (typically 10-30mi but in congested airspace can be closer to 100mi) from the air field. This saves them time, money, and distance.
After a pilot requests this, the controller will often request they report if or when they can navigate to the airport under VFR conditions and switch them to a much quicker and more direct VFR approach.

Nope. That's a visual approach, which has nothing to do with VMC climb/descent. VMC climb/descent is specifically used in procedural (non-radar) areas, so it has nothing to do with avoiding radar vectors.

@ J. Hougaard - The visual approach often comes AFTER the request for a visual descent, read the answer - I explained that. The VMC descent is sometimes used by pilots to signal to ATC that they may be a good candidate for a visual approach but it is not a done deal possibly because of distance or the airport not in sight .


text:
What is the procedure for a rejected Jet/Rocket Assisted Takeoff (J/RATO)?
Seeing the image of a Lockhead LC-130 doing a jet assisted takeoff in snow mentioned in this answer, I wonder:
What is the procedure for a rejected takeoff when using JATO?
Can the JATO rockets be turned off once ignited?

(Image source:  Wikimedia Commons)

JATO (more correctly: RATO) typically uses simple solid-fuel rockets for their ease of maintenance, simple construction, long-term storability, robustness, and reliability. However, a simple solid-fuel rocket has to burn out once ignited, there is no way to shut it down. Techniques for extinguishing and even throttling solid-fuel rockets do exist, but they were developed rather recently, have not yet been commercialized, and clash with the goal of simplicity.
Currently, the "usual" way to shut down a solid-fuel rocket is to rapidly decrease the pressure in the combustion chamber, aka an explosive Flight Termination System, aka blowing up the rocket – not something you want to happen with a rocket strapped to your wings (IOW directly below the fuel tanks). Alternatively, you could get rid of that extra thrust by jettisoning the rockets. Having a dozen or so flaming projectiles uncontrollably flying around the airplane is also not a good idea.
So, you either reject before igniting the rockets or you don't reject at all. V₁ is when you hit the button, which may be as low as 0 kt, depending on the specific application.

I'm curious about extinguishing a solid-rocket motor. You say one way is to rapidly depressurize the combustion chamber, "aka blowing up the rocket". Isn't that the opposite of decreasing the pressure?

The space shuttle had an explosive charge on the side of the SRBs that would cut them open to release the pressure.  These were used by range safety, after the SRBs were separated during the Challenger accident.

Actually, extinguishable solid-fuel rockets have been around since the early 1960s, having been developed to allow solid fuels to be used in an ICBM without their inherent burn variability completely ruining the missile's accuracy.

Once the rockets are ignited, it is basically too late to abort the takeoff, so the decision would have to be made before doing that. This is one reason why RATO is not used today as much as it used to be, the increased power of modern turboprop engines reduces the need for it in any case.

Specific to the LC-130.’
After ATO ignition but prior to flying speed, a reject is performed by retarding the throttles to the ground range. If you can reach a flying air speed - you typically are not using ATO - unless the terrain is such that warrants a shorter slide to protect the airplane from higher risk.
The bottles burn, based on pressure altitude and temperature, for approximately 15 seconds.
The term “Jet Assisted” comes from the use of a solid propellant motor that produces its thrust by use of a “jet” or stream of hot gases through a rocket nozzle (a more literal use) appropriate of the time they were designed (early 50’s).

authors: الهام کامگار


text:
Are compressor maps for multistage compressors drawn for one blade row or the whole compressor?
Apologies if this is a stupid question.
I am a little confused about compressor maps.
Are compressor maps such as this one, drawn for one blade row only or the whole compressor?

(source: Wikimedia)
If it is for one blade row, can you predict the behavior of the next blade row from the compressor map of the previous row? Like, I am guessing that the blade rows of say the HP compressor have the same speed lines because they are on the same spool, so would they move up or down the speed line?
If those maps are drawn for the whole compressor, then does that mean that all blade rows have the same operating conditions (in my opinion, they should have different operating conditions)?
Any insight would be really appreciated! Thank you!

@Bianfable Thank you for your insight! Yes, regarding operating conditions in a blade row, I meant N, P, T and also efficiency. I also meant would different blade rows be at the same point on a compressor? Like say you are running at low power settings, I believe that in this case the first stages can stall due to high incidence, and the rear stages can choke because of the annulus area decrease. But the surge line is for me at a different point on the map then choking conditions. So would different "dots" be used to represent that?

The compressor map is used to account for the performance of a whole compressor by taking various parameters into account- mass flow parameter, shaft speed, pressure ratio, efficiency & Reynolds no. Pressure ratio parameter is essentially the ratio of pressure at the exit and entrance of the compressor, Mass flow parameter and Shaft speed parameter take the Temperature at the entrance into account. So as the characteristic map is based on the entrance & exit parameters of the compressor, the characteristic map is representational of performance of compressor as a whole.

For low power settings, I would say lower spool speed and mass flow as well as lower pressure ratio i.e. at the leftmost side of the characteristic map. As you mentioned the rear stage is choke as no more mass flow can pass through it, the initial stages will stall.  If you try to locate this on the map using numerical values, you will reach a surge line, if I am not wrong. I believe you are trying to relate this with the stage of a compressor, but that isnt the case for the characteristic map which is scaled to starting & end conditions. Also, operation is governed by choking of rear stages.

The image you are referencing is definitely an entire compressor.  You can tell because the pressure ratio axis goes up to 17:1.  You won't get 17:1 out of a single blade row, ever. One-tenth of that would be more likely for a single stage.  i.e. this could be a 10 stage compressor with each stage contributing a 1.3 - 1.4:1 pressure ratio.
I've only ever seen compressor maps like this drawn for entire compressors.  Not to say you couldn't do a single stage, but I've not seen it done.

This answer already answers:

Are compressor maps such as this one, drawn for one blade row only or the whole compressor?

The shown compressor map is indeed for an entire compressor as can be seen from the pressure ratio.

If it is for one blade row, can you predict the behavior of the next blade row from the compressor map of the previous row?

No you cannot predict the behavior of the next row based on a single stage map, single stage maps do exist though. In theory you can stack these maps to create a complete compressor model, but various loss models prevent that you get an accurate representation. But, since these maps are very hard to get, performance engineers are happy to get these data even if it is a stage map. Also, when modelling gas turbines you may want to split a compressor to model the flows or torques at a certain stage more accurately. We've done this in the past to calculate the individual stage torque contribution of a 3 stage fan of a low bypass turbofan fighter engine.

I am guessing that the blade rows of say the HP compressor have the same speed lines because they are on the same spool, so would they move up or down the speed line?

The smaller the blades the more important losses become, e.g. a constant tip gap in the compressor will have a smaller effect on large compressor blades than it will have on smaller blades. This means that efficiency and pressure rise are lower the further down the compressor stages, on the speed line the operating point would go down the speed line.

If those maps are drawn for the whole compressor, then does that mean that all blade rows have the same operating conditions (in my opinion, they should have different operating conditions)?

As the air is compressed, the inlet conditions for each stage are different. The axial speed is the same though.


text:
Why was this commercial plane highly delayed mid-flight?
What could be the main reasons for a short-haul flight to be delayed over an hour in-flight?
Recent Lufthansa LH 2227 CDG-MUC flight took off only half an hour after scheduled time, but landed at destination delayed nearly an hour and a half.

Meaning (if I am reading these stats correctly) that this particular flight spend an hour extra in the air over scheduled time. I begin to question if there is enough fuel for the plane to stay that long extra?
I flew the very same flight few days ago and that flight also took of half an hours after schedule and landed fifteen minutes after schedule. Meaning that a plane manage to "work out" half of its delay en route. This particular, pictured flight not only didn't work out its initial delay, but also added another hour to it while being in air.
I was always told (and saw that in my small commercial flying experience) that

short- or middle-haul flights delayed 15-30 minutes on take-off,
long-haul flight delayed 60-90 minutes on take-off,

are nearly always able to land on-time, effectively "working out" their initial delay during flight, by flying faster etc. What happened or could happen here?

Don't forget departure is from the gate and arrival is again at the gate. Take off half an hour after departure is pretty much right on schedule for large airports. It also can't fly much faster to catch up with a delay—there is simply quite a lot of buffer in the schedule.

"I begin to question if there is enough fuel for the plane to stay that long extra?" Well it would be pretty obvious if there wasn't enough fuel, no?

@DavidRicherby That was a theoretical and more general question (not concerning this particular example) if plane departing for 1,5h long flight takes a spare fuel for extra 1+ hour of flight (thus around additional 75%). Directly saying this question should be understood as "I begin to question if this plane actually spent extra hour in-flight or whether there were some other circumstances that caused that huge delay". Which turned to be true.

If you look at the details, you’ll see the aircraft left the gate at 9:37, but only took off at 10:47.
They probably received notice of the issue in MUC pointed out by Machavity while taxiing to the runway (and then asked to park somewhere waiting for the airport to be ready for them). No sense returning to the gate for a delay like this which is expected to be relatively short.
A possible alternative (though probably not here) is they they had an issue right after gate departure which triggered a maintenance request. It happened to me once on some regional airliner which had an issue just when they spooled up the engines (or just after a few meters, don’t remember). Immediately powered down and had some part of the engine changed (or maybe just a filter or something similar) while we were waiting, took about an hour or so.

It seems that your answer is much closer to the actual situation than Machiavit's answer above. Flightradar24 confirms that this particular flight took off at 10:46 and that the actual flight time was nearly exactly the same as average flight time (1:08). Thus this is better answer to my question, as I was asking why this plane spent over an hour extra in-flight. In fact it didn't.

Another alternative, since the gate departure was quite late, is that they had to wait that long for a runway slot. That's happened to a flight I was a passenger on (or, at least, that's what the pilot told us was the reason for sitting an hour).

@PeterTaylor In my experience, this just doesn't happen. A slot is just a capacity concept used to measure how many movements an airport can handle, and is used for capacity planning and "selling" those slots. Once an aircraft is ready to go, it just goes towards the runway and queues on the taxiway until it reaches the runway (mostly first-come first-serve, though there are some priorities as well). Waiting on the ground would be more an ATC hold related to the lack of capacity at the destination airport. But I'm just a passenger, maybe commercial pilots around can infirm/confirm.

I've also had a maintenance issue after leaving the gate: there was a problem with the towbar during pushback and they needed to get the maintenance techs to check the nose gear hadn't been damaged. I think that cost us about an hour.

@jcaron Once the aircraft starts moving away from the gate, it's usually first-in-first-out, right? They can only hold so many planes on the passageways to the runway.

@Mast, yes, in my experience, this is usually the case. For a plane not to go queue close to the runway usually means something special is going on.

@jcaron I've seen a really loooong queue at the runway when there were surrounding weather delays. First all the flights were stuck at the gates waiting, and then once departures resumed they all wanted to leave ASAP. This was a large airport that could fit a lot of planes in queue. (I don't know if leaving the gate to sit by the runway has some advantage for airlines...maybe they get to count that as departure time, or maybe they think it makes the passengers feel like the plane is going somewhere faster.)

Munich was closed for a short time due to a security breach

The airport tweeted: “According to the information currently available, a person has probably entered the clean area of Terminal 2 through an emergency exit door from the unclean area.
“As a result, police measures are currently in progress.”
Terminal 2 is the home of Lufthansa, which operates hundreds of flights through Munich each day.

And this is likely the main kicker for this flight

While arriving flights are currently being allowed to land, the airfield is filling quickly and diversions may soon begin.

The plane probably circled as long as fuel margins would allow, rather than sit on the ground in a long line.

It might have sat on the ground—the aircraft is only considered arrived when it stops at the gate and shuts down.

According to FlightView, LH2227 did not take off until 10:46 AM.

Thank you for your detailed answer. While airport closure could be a good reason here, the answer below given by jcaron (and comment above) are in my opinion more exact solution to this particular case, so I decided to accept the other answer.

re 'working out delays'
The flight uses an operational flight plan which shows the routes (waypoints), speed, altitudes. There are usually some compromises made, a shorter route may cost more (overflight fees) and a cheaper route may take longer. The company will usually select what is best ie more economical with flight time acceptable.
In exceptional cases like longer delays, the ops dept may choose a higher cost route to minimise the impact (more direct route or higher cruise speed). This is usually easier to do on longer flights of course, on shorter routes there may not be much choice.


text:
Where, exactly, is the Boeing 727's FDR located?
I'm working on a history report and I am trying to find a diagram that shows where the flight data recorder would have been on a Boeing 727 in 1984, specifically for Eastern Airlines. I know the general answer is "tail section," but I'm looking for a specific location, ideally with a diagram.

Hopefully someone can confirm this but in the freight conversion 727 it was in the rear cargo hold, just aft of the door. But I might be thinking of DC-10. It's been many years.

That’s true of the freighter. I don’t believe it was moved from the passenger version either, but I am not 100% sure of that.

I’m specifically asking about a passenger plane (sorry for being unclear). I know the CVR is in a cylindrical orange tube near the aft staircase, but I’m looking for the FDR’s precise location.


text:
Can an ARINC 429 controller set to receive messages on high-speed (100kHz) see 12.5kHz messages?
I am working with an ARINC 429 controller which is currently set to receive messages at 100kHz. When the transmission line sends messages that are 12.5kHz (standard ARINC 429 low speed) the controller can see them.
Is this normal for an ARINC 429 controller?

That is normal for an ARINC 429 receiver. The clocking for ARINC 429 is built into the transmission data, with the bipolar Return to Zero format having a Null for the last half of each bit time and requiring 4 bit times of null (0) voltage between labels. This lets the receiver adjust to the data rate automatically.

At first glance, it seems like some curious behavior. Right now I am developing an API for an ARINC controller in C#. This is one of the things I encountered while testing the different speed settings of the controller. Thanks.


text:
What is the technical term for ARINC 429 data injected into a heartbeat stream going to an LRU?
I am going to describe a type of communication protocol that I've seen used with ARINC 429 and would like to know if there is a proper name and classification for this type of communication... Anyway, I'll try to describe as accurately as possible.
So there is an outgoing stream of communication (like a heart-beat) that an LRU expects to receive. The LRU also expects to receive certain data on that same heart-beat bus... So, you'd have to sort of inject the ARINC word data into the heart-beat stream temporarily to send it to the LRU.
Is there a name for that sort of communication?
I think I've also seen similar protocols with serial communications... Where a data stream (heart-beat) is always being sent, but the pay-load changes when you need to transmit/receive meaningful data.
I am looking for the technical terms to describe this communication process.

are you asking specifically for ARINC 429 or in general serial communication interfaces?

Is it possible the OP is referring to Williamsburg/Buckhorn protocol in which there is a "Request to Send" and a "Clear to Send" from the respective transmitter/receiver. Once the handshake is made, the data transfer can begin This (page 17) is a slightly better description. I know it's not quite a "heartbeat," but from my experience with standard ARINC 429 at least, the data transmission is continuous. If the data hasn't changed, the same data just gets repeatedly sent... There is no idling as far as I know?

@mins Yeah, I see what you're saying. I guess I'm just not really clear on what's being asked. I was taking a stab with the W/B protocol as that is a somewhat unique protocol to ARINC 429. It'd help to know what protocol (429, 615, 573, etc...) the OP is referring to? It might be a little easier to make an inference about what they're asking that way.

I'm assuming the OP is referring to ARINC 429 based on previous questions, hence my edit to the question

@selectstriker2 Yes, I am only referring to ARINC 429. I shouldn't have said the thing about the serial communications as I believe that it confused what I was trying to ask. I was only using that as an example to say that I believe I've seen a similar kind of pattern involving serial communications in the past... and was not asking about serial communications here in my question. Thanks for clearing that up.

ARINC 429 is both an electrical bus standard and a data standard.
The electrical standard defines a unidirectional, one to many (Tx to Rx) serial data bus that is transmitted using bipolar Return to Zero (RtZ). This makes the signal self clocking. If no data is being transmitted, the line stays at 0 VDC (Null) which consequently removes the clock as well.
Since there is only one transmitter on a line, there isn't any "injection" of data onto the bus by another source.
The ARINC 429 Data standard uses the serial bus to transmit packets of information, called labels. These labels are 4 bytes (32 bits) long.
An ARINC 429 receiver is designed to expect a constant stream of labels to update the receiver's internal data within a certain time limit. If a label isn't received within the specified period it is considered stale and is left to the receiving LRU to decide how to handle stale data.


text:
Does the Airbus A320 or Boeing 737 have better resolution screens in the cockpit?
I know this is kind of a specific question so if nobody knows it's fine. Does anybody know if the Airbus A320 or Boeing 737 has better resolution cockpit screens like PFD and ND? ( For the Airbus A320 I also mean the new screens like some A320 have more circular cockpit screens and the new ones are more square and look more defined
Here's the new screens, well it's not new but it's better

Here is the more circular screen

I made edits to the title, but I also recommend that you also crop the pictures so that the pictures only (or relevant labels) are visible. Simply attempting to ascertain which picture refers to to plane was quite difficult.

Which 737? There's three different 737 generations with different displays, the Classic, NG and MAX. The new screens you refer to on the A320 is called the EIS2, which are LCD versus the CRT of the EIS1.

By better resolution screen do you simply mean higher resolution or are you looking for a higher pixel density?

B737NG DUs (Display Unit) have a resolution of 1152x1152, as per the maintenance manual. The display size is 18x18cm, making it around 163 PPI.
I have found a source that claims A320 PFD has a resolution of 768x768 and the display size is 158mmx158mm, making it around 123.4 PPI.
I imagine B737 MAX is using the same 15.1" display as the B787. In this case, the resolution is 1400x1050, and the PPI would be around 116 PPI.

Of course 737-NG is some 10 years newer than A320, so using slightly better screens are to be expected.

Actually, the displays on the 737NG are probably roughly the same as for the B777, so they are not that new. Add to that, the first A320 with LCD display units was produced in 2009, whereas before that, the A320s were equipped with CRT displays.

They are not that new, but still a couple of years newer than A320. Yes, I know A320 was originally CRTs, and thought they didn't want to change the resolution when switching to the LCDs to avoid having touch the software, but than I realised they touched the software anyway, because the newer version comes with somewhat simplified symbology.

I wonder where one could get those square LCD panels. They'd make a wonderful HAL-9000-like workstation.

@rbanffy or use a cheap consumer 27" display and put a plate with square cutouts in front of it. That's how many home cockpit builders go along.

That's cheating, @Emile.


text:
Can a wide body airliner land safely with a full fuel tank?
Can a commercial double-aisle jet aircraft (e.g., 777, A330) land safely with a full fuel tank (minus the fuel spent on taxing and takeoff)? Has that ever happened?

Those big tubeliners are well over their maximum landing weight with full fuel tanks, so I will guess that the answer is no. They can however dump fuel, or just fly circles to burn it (both have happened) before returning to an airport.

Maybe we should consider "emergency" e.g. one or even both engines lost, so you are probably in range of a runway, but cannot dump fuel in the remaing time.  I assume yes, but you will likely damage the landing gear, the airframe or even the runway.

As long as you don't exceed the maximum landing weight of the aircraft, you should be fine.

I note you've subtly changed this question, does my answer still address your question or is there something more you wanted to know?

@Jamiec That it does. I already had a safe landing in mind. I edited the question to clarify what I meant by landing as pointed out by one of the users in the comments section.

The other part of not having a full load of fuel onboard, is that there's less to burn should the landing go badly.   A full load of burning jet fuel will hamper evacuation efforts severely.

Can a wide body airliner land with a full fuel tank?

Yes! But it is safer to land an aircraft below its published MLW.

Wikipedia has the relevant specifications for the B777 and the A330
Using the B777-200 as an example.
Maximum take off weight: 545,000 lb / 247,200 kg
Maximum landing weight: 445,000 lb / 201,840 kg
So this particular aircraft may have to drop roughly 46,000 Kg of weight if taking off at its maximum before it can land safely. That's not to say it's impossible to land without doing so, but it's certainly not advisable.
When an emergency presents itself, what is "advisable" is getting on the ground as quickly as possible, and if that means landing overweight then so be it. There have been plenty of times when an overweight landing has caused no damage - and even if the aircraft is damaged by an overweight emergency landing, that's still often a better outcome for the people on board than would be the case if the aircraft waited to get below its MLW before landing.

However, with that said, just because you are taking off with a full load of fuel it does not imply that you must be at MTOW. You could be taking off with a full load of fuel but no cargo/passengers, in which case it is entirely possible that you may be below MLW. And in which case the answer would be yes, it's entirely possible to land with full fuel tanks.

You can definitely land all civil airliners above the MLW, its just going to require the aircraft to be taken out of service and undergo checks before flying again.  The excess tolerances airliners are built to these days means the margin between MLW and structural failure is fairly significant, not razor thin.

@Moo I never indicated otherwise. It's still inadvisable AFAICT - show me a SOP which says "Yeah, go ahead and land above MLW, we're happy to lose potentially thousands of pounds while we take it out of service"

@Jamiec "We're happier to lose thousands of pounds inspecting after an overweight landing than deal with the bad publicity and law suits from a crash." :)

@Jamiec: I don't know where to find airline SOPs to show you (are they even public?) but I've frequently heard that they typically advise an overweight landing in case of, say, a life threatening medical emergency on board.

Note that the question is whether or not they "can" which is a clear yes, it is indeed quite possible. I believe that the OP would be better served with an answer which says so clearly and what the considerations and consequences are rather than explicitly saying that to do so safely you must be below landing weight.  There are situations where an immediate landing is MUCH safer than waiting (cabin/cargo fires in particular come to mind), and I myself have landed airplanes overweight on more than one occasion and the inspection didn't uncover any damage of any kind.

@Lnafziger good idea, go ahead and write it.

Yours is mostly correct, and the addition of one or two sentences would make it even better!

@Lnafziger do you not think I covered that in That's not to say it's impossible to land without doing so, but it's certainly not advisable.? I get the point about immediate emergencies - I just think thats kind of implicit! In any case answer updated, let me know if it can be worded better.

So, it's your answer and I'm just trying to suggest what I feel is an improvement.  Take it or leave it, but I think that "It depends if the fuel takes the airliner above MLW." as the initial answer and "not impossible" is pretty far away from "it's not a normal procedure, but commonly done in certain situations and is even demonstrated during certification."

@Lnafziger Lets get something straight right up front - you absolutely know more on this subject than me. I initially answered this question rather flippantly from the knowledge I have. It's improved (arguably) over time ans is what it is. I honestly feel a bit fraudulent having earned rep from an incomplete answer. I'm making this a CW now. I am happy to continue this discussion - but its bett er off in [chat] I'll be happy to join you. Otherwise, you could definetly write a better answer, or update this one.

They can land safely with full tanks but they will need the gear checked before they can take off again. It's not unheard of, if you search for "overweight" on avherald you can see a list of them They will be marked as A38* or B77*.
For example this flight landed with a weight of 523t while the max landing weight of that aircraft is 394t.
If possible they will prefer to dump fuel or stay in the air to burn it off.

If there's a serious time-sensitive emergency, landing overweight is likely to be a far better plan than waiting around while burning off or jettisoning fuel. As others have noted, an inspection, which involves time and money, is required after an overweight landing, as it stresses components, but aircraft are designed with structural tolerances to allow such a landing when necessary.
You might be interested in reading this Boeing AERO article (from 2007) on factors to consider when deciding whether to land overweight or to delay landing until below maximum landing weight:

Landing overweight and fuel jettisoning are both considered safe procedures: There are no accidents on record attributed to either cause. In the preamble to Amendment 25-18 to FAR Part 25, relative to fuel jettison, the FAA stated, “There has been no adverse service experience with airplanes certificated under Part 25 involved in overweight landings.” Furthermore, service experience indicates that damage due to overweight landing is extremely rare.
Obviously, landing at weights above the maximum design landing weight reduces the normal performance margins. An overweight landing with an engine inoperative or a system failure may be less desirable than landing below maximum landing weight. Yet, delaying the landing with a malfunctioning system or engine failure in order to reduce weight or jettison fuel may expose the airplane to additional system deterioration that can make the situation worse. The pilot in command is in the best position to assess all relevant factors and determine the best course of action.

Ultimately, it's a judgement call where the crew needs to assess the severity of the emergency, the likelihood of the situation to get worse, available runway length, and all other available information to decide whether an overweight landing is the best course of action.

Not a general answer, but in the book Flight Testing of the A380 by Claude Lelaie1, the main test pilot of that aircraft, he clearly states that during the test period, they landed the aircraft several times well over the MLW without any problems.
But, of course, these were test pilots...
The MLW is designed as a general limit that ensures that safe landing will be possible whatever the weather, runway length... and pilot performance! I assume this must be the same for all contemporary airliners.

1 amazon.fr link (French), amazon.com link (English).

@ymb1 Thanks for useful edit. Funny, I realise that the publisher chose a different cover for the english edition, much more dramatic, with a tail strike demonstration ;)

Yes, you can safely land with full fuel. There are many Boeing 767 and Airbus A300, A310, and A330 that no not  have fuel dumping capability. They just land overweight in case of an emergency and then do an overweight landing inspection.

737s also lack fuel-dumping equipment.

I recall watching a documentary on the development of one of the newer larger jets - either B777 or A380 in which extreme braking tests were performed as part of the certification process. The test was to evaluate gear/brake performance for either a rejected takeoff at MTOW or overweight landing, using brakes only (no thrust reversers). Heat accumulated in the brakes transferred to the tires (not unexpectedly), either initiating fires or at least overheating them to the point that several burst. Part of the test protocol was that firefighting had to stand by for several minutes before engaging the fires in order to represent a typical response time. It demonstrated that although the aircraft could stop safely and the brakes had the capacity to do so, the amount of heat produced was almost certain to cause damage and posed a significant fire risk.


text:
Why not just drop an engine on fire?
I am interested in the case of Qantas Flight 32 and similar incidents, where there was a fuel leak after a number two engine explosion due to the disintegration of the turbine disc. It was a very dangerous situation since the fuel leaks were very close to the failed, then burning, engine. And to make the matter worse, fuel dumping system was down due to hydraulic failure.
Although the crew managed to shut it down, the engine took considerable amount of time for fire to be extinguished completely.
I wonder in those kind of situations, could adding eventually a "drop-engine-on-fire" feature make the situation less dangerous?
You may consider the following:

Modern airplanes could fly with one engine out.
Dropping the engine must be in water to not cause any harm to the people below.
Usually, the engines are mounted on the wing only at three points.
Even if the main evidence of the investigation (that is, the burning engine) will be lost and maybe never found, I think that saving lives is a bit more important.

EDIT :
In response to comments, I think that every feature (even if its seems silly) is subject to pro-con studies. For example, Boing 747 had fuse pins  that are designed to break cleanly in case of excessive loads/vibrations.

Aircraft fires are already very rare and this idea would work only in very limited situations (aircraft over water, the fire doesn't damage the drop mechanism, the extinguishers don't work). You also have more engineering costs (e.g. fuel lines should seal properly after dropping), probably more weight, and an aircraft with engines that will drop off if one system malfunctions or the pilot hits the wrong button. Passengers probably won't like that last point, by the way. All in all, it's hard to see a definite advantage.

You may not know that dropping things of this size into sea is not allowed, by international conventions, unless the area is free of ships and a permit has been granted (this is also valid for jettisoning space vehicle elements).

@mins:  Doing whatever is necessary during an emergency is virtually always allowed.  No Clean Water agency is going to pursue Capt. Sullenberger for throwing trash in the Hudson.

@abelenky: Of course (that's not specific to aviation). But the usual way is to prevent a possible need to endanger other lives, damage properties or our environment by other means, like more efficient extinguishers. Indeed the responsibilities could be determined, and someone may have to pay (usually insurances). Hudson accident included, if damages exist.

At first glance, given the very small number of engine fires, it seems there could well be more damage caused by accidental activation of the engine jettison system than would be prevented in cases where it's needed.

"Usually, the engines are mounted on the wing only at three points." That is true so far as it goes, but it rather misses the reason why the engine was there at all - to apply a force to the aircraft!". Those "three points" are actually quite complicated structures which already contain failsafe devices to prevent "accidental" disconnections. Designing a connector that can transmit something like 50 tons of engine thrust, and also be disconnected remotely even after possible damage from fire, etc, would be far from simple - not to mention testing that it actually worked as intended.

@alephzero:  Beyond making sure it works as intended, is ensuring that it NEVER accidentally activates.  I can think of few things worse than having a perfectly good engine inadvertently detach when it is most needed!

@abelenky One thing that would be worse than accidentally jettisoning an engine, especially on a twin, would be to accidentally jettison two engines. :)

@abelenky But you also have a lot of risks dropping on land. You don't want to be dumping engines over e.g. New York City. And can you imagine those lawsuits? shudder

Car engines catch fire too. Why not just install an engine ejector mechanism in every car? I hope you can see the absurdity of this idea. Ejecting a jet engine from a wing would be even more complicated and risky than ejecting a car engine.

Not an aviation engineer, but wouldn't dropping an engine cause balance problems?

I hope the OP is not an engineer :-).

«fuel dumping were down » I can’t parse that.

Not to say there aren't good reasons against dropping engines, but the comments and some of the answers are treating this question as if the idea was ridiculous. It's not unheard of for aircraft engines to be designed to detach in some situations to prevent further damage. Engines are often attached by fuse pins so that they will separate in cases of excess force or vibration. So preferring separation over further damage is a valid option which I'm sure designers have considered. Engines falling from the sky are certainly not a good thing, but better than entire aircraft falling from the sky.

It could land on someone's head. It could also be repaired.

@reirab To jettison one engine may be regarded as a misfortune; to jettison both looks like carelessness.

As the poster wrote, "The main reason for asking is to discus the idea and evaluate the benefit/cost ratio." : This is not a discussion site, and extended opinionated discussions are discouraged.

@mins an area is very likely to be free of ships after you drop a burning passenger plane engine on it. So, I guess that can be taken for granted.

The current position of regulators like the FAA is that dropping things off of airplanes in flight is a bad thing. Dropping extremely large and heavy things like engines would be extremely bad. This poses an unacceptable risk to people and property on the ground (or even in the water). Most aircraft with engine fires do not kill anyone on board, so why risk killing people on the ground?
The preferred method of dealing with engine fires is similar to that of fire protection for buildings; take steps to prevent them, and provide methods for putting them out should they start. We don't go blowing up buildings that are on fire just because it might be quicker than putting it out.
So instead manufacturers are required to provide many features to prevent fires. Areas around the engines are separated into zones by firewalls and seals, required to prevent spread of fire. Any flammable fluid is required to be contained and drained, and separated from ignition sources.
If a fire does start, the engines have fire suppression systems installed. The system has to be tested to show that it provides the required suppression to a fire, and the aircraft generally carries enough suppressing agent for at least 2 uses. Even if this doesn't work, the isolation features built in should prevent the fire from spreading, and possibly allow it to burn itself out of fuel or oxygen. In most cases an aircraft is close enough to an airport to land before this becomes an issue.
These measures have been shown to be adequate. When was the last time someone died because of an engine fire on an airplane? Fires are extremely rare, and fires that can't be dealt with by the existing measures are even more rare.

There are many more reasons why dropping engines is a bad idea.
Some designs allow an engine to shear away from the wing in the event of a crash, but this is not designed to work in flight. Aircraft that drop items like weapons in flight require extensive design and testing to make sure that the object will drop away from the aircraft properly. An aircraft in an emergency like an engine fire could be making extreme maneuvers that would make this even more difficult.
Objects like weapons that are designed to be dropped regularly still malfunction. How can you make an engine that's been installed for decades separate reliably? If you are relying on this feature for safety, there will be added cost for designing, installing, and maintaining the system. Those costs could be reduced if you don't rely on the feature as much. But then if the current measures are enough, why accept that extra expense?
Investigators generally take interest in engine fires. If you drop the engine, there goes the best evidence for figuring out how the fire started, and what could have prevented or mitigated it. Something large like an engine would be easier to find than smaller parts, but there is still the risk of loss or damage hindering the investigation. If the problem is bad enough that airplanes are dropping engines, it would be better to fix the problem than address the symptoms.
If you constrain pilots to only dropping an engine over water, this complicates things further. There are already rules about where airliners can dump fuel, but dumping fuel is generally a less stressful situation. The pilots chose to stay in the air and dump fuel, so any emergencies are generally less urgent and they have time and attention for where they could dump fuel. If there's an engine fire that requires jettison of an engine, things are going to be more hectic in the cockpit, and it may not be the best time to be considering where this would be allowed, taking things like trajectory into account. And going back to the cost issue, if this would be limited to only areas over water, you couldn't rely on this option to always be available, so is it worth the cost?
Airliners can fly with an engine shut down, but missing an engine is a different matter altogether. The aircraft is required to be tested and certified in many different conditions with an engine shut down. How can we test this with a missing engine? Do we drop an extremely valuable engine every time we test? Do we just make the flight with one engine, which is still in testing itself? Do we not test, and accept that after going to all the trouble of allowing jettison of an engine, the aircraft may not be controllable in some situations?

+1 for We don't go blowing up buildings that are on fire just because it might be quicker than putting it out.

I can just imagine it now - please welcome the new Chief of the Fire Dept, Michael bay.

In particular the FAA has specific regulations about dropping things (FAR 91.15). I would submit that dropping your engine "creates a hazard to persons or property" (unless we constrain pilots to dropping their engines over open ocean with no vessels around, but as fooot noted telling a pilot "Please carry your burning engine 50 miles offshore before you drop it!" might be asking a bit much.

Also in regard to testing aircraft with a missing engine, aircraft engineers tend to design for the worst case: Engines have ripped off in flight and the plane has returned to make a safe landing, so at least from that angle it's theoretically possible to have a more orderly detachment executed safely - aside from the whole "giant hunk of metal falling from the sky" problem and violating FAR 91.15 anyway.

Dropping things from a plane is bad? what about the planes toilette's?

Counterpoint to We don't go blowing up buildings that are on fire just because it might be quicker than putting it out: 1906 San Francisco earthquake (which admittedly didn't work); also oil well fires and bush fires.

@tuskiomi That is a myth and not based in reality. The reality of it is that the "blue ice" falling from planes in the 70's was because of leaking systems, not intentional discharges. Planes have not purposely ejected lavatory waste since somewhere around WWII.

@Wolfgang I mentioned it because, like dropping an engine, I know that explosives can remove danger of fire, but that in almost all situations it is overkill and worse than alternatives.

@fooot Agreed, and point taken. I certainly wouldn't advocate adding to building codes the mandatory installation of explosives in the foundations.

"Dropping extremely large and heavy things like engines would be extremely bad. This poses an unacceptable risk to people and property on the ground." -- This probably goes double when the large and heavy thing is currently on fire and likely to explode.

Given that jet engines provide not only thrust but also electrical, hydraulic power as well as bleed air into the airframe, as well as draw fuel from it, there are a lot of connections which would need to be disconnected and properly sealed off/terminated before an engine could be released from an airframe without creating new complications or emergencies. A lot of extra complexity and risk to do what is already a bad thing. Note that there have been cases of engine separation at designed-in shear points where the result was critical airframe/system damage causing a crash.

Would you trust an ejection system to fire a complex series of processes in order and with correct timing on a system that is known to have been compromised by fire? The most likely possible outcome being the engine flipping over and sheering off the rest of the wing?

Something else to keep in mind is that dropping the engine seriously changes the flying characteristics of the aircraft. Not just the aerodynamics change. but the center of thrust and center of gravity as well. Aircraft that literally lose an engine often crash as a result (think the ElAl crash in Amsterdam, though there was more wrong there, the falling engine tore out hydraulic lines and part of the leading edge of the wing as it detached).

@jwenting In that crash, the falling engine also tore off another engine as it detached, IIRC.

@reirab correct. And from the AIB report it becomes clear that that wasn't the first time this had happened. If the aircraft is turning during separation especially, it can be expected that the engine will hit other engines or aircraft structures unless it is forcibly ejected away from the aircraft (as happens with military stores, which are either ejected by pistons, explosive bolts, and/or positioned carefully in the airstream in order to separate cleanly).

The fact that the modern aircraft could fly with one engine out does not mean that the offending engine should be dropped. It is better to have it in the aircraft rather than risk the engine taking off with a chunk of aircraft. After all, in case of El Al Flight 1862,

... engine no.3 and its pylon separated from the aircraft and damaged part of the leading edge of the right wing. The no.3 engine then struck engine no.4, causing this engine and its pylon to depart the wing.

Uncontained engine failures are rare and in case of most engine failures, the fire, if there's any is extinguished quite quickly. Also, in most cases, dropping of the engines is not going to wait until a (suitable) water body is found. In case of failures during takeoffs/landings, like the American Airlines Flight 383 or the British Airways Flight 2276, the pilot will have one more thing to worry about.
Then there's always the possibility of uncommanded detonation and failure to detonate when commanded- this will add further checks to the maintenance schedule. Once the engine has been jettisoned, the fuel and other lines have to closed. All this adds complexity to the system, which may well be not worth the cost.
Finally, the engine weighs quite a lot and dropping it would affect the aircraft's weight and balance. This could be a problem if the aircraft is maneuvering, requiring the pilot to take this sudden change into account.

The experience of El Al 1862 is probably the best argument against a system that would intentionally drop an engine.

@MichaelSeifert indeed. Even had there been no further structural damage the aircraft, minus an engine, would have been far harder to fly than had the engine simply failed and remained attached. It was in the end of course not the engine falling that caused damage on the ground (it fell harmlessly in water) but the aircraft spinning out of control while trying to turn to land and crashing into an apartment block.

Can remember that accident and the aftermath. The aircrew telling ATC "we've lost an engine" and them thinking it had failed when in fact it had fallen off was a classic example of misunderstood communications in aviation. Later met one of the firefighters who'd responded to the scene, not nice stories.

Of course, the problem with El Al 1862 was that the separation was not by design, but because of a pylon failure. It tore off, with significant lateral forces. That's how the #3 engine took out #4 as well as damaging the wing. An intentional drop would presumably have no lateral forces, so the engine would drop straight down.

@MSalters:  One would hope that the engine would drop straight down, but airflow around aircraft does funny things.  See this video (also linked in fooot's answer) of an object being intentionally dropped.

A major issue is that it's not really the engine itself which is on fire, in fact they are supposed to be on fire in a sense. In many cases an engine fire really means that you have lost control of the fuel/hydraulic fluid flow to the engine. For example if a turbine blade detaches, penetrates the engine casing and cuts a fuel or hydraulic line.
Indeed in the example in the question the damage was caused by the original engine failure and resulting fragmentation rather than a fire in the engine itself as such.
Even if you drop the engine you've still got fuel spewing out and burning so unless you can stop the fuel leak at source you haven't really solved the underlying problem and if you can cut off the fuel dropping the engine doesn't achieve much.
If you've got a leaking tap cutting the tap off with a hacksaw isn't a solution.
You are then also in a situation where you have created a whole new risk of accidentally dropping the engine. There are also lots of fuel, sensor, hydraulic, compressed air and other connections to a jet engine and unless you can guarantee separating all of these cleanly you run a very real risk of doing even more damage or even worse ending up with an engine half hanging off.
There is also the fact that while aircraft are deigned to fly with one or more engine failures actually dropping and engine is going to have a fairly dramatic effect on the trim of the aircraft just in terms of the missing mass.

If you've got a leaking tap cutting the tap off with a hacksaw isn't a solution. +1

The first reason I can think of is that an aircraft engine on an intercontinental jetliner weighs about 6000-10,000 lbs depending on the type and simply jettisoning the thing would significantly affect the weight and balance of the craft, making things worse.  An object that size simply released from the jet presents other hazards such as tumbling and then striking the airframe upon release, causing catastrophic damage and possibly departure from controlled flight.

That was my first thought too and made me smile quite contently.

Or, how about where this flaming 10,000 lb hunk of metal lands?

It would definitely shift the balance but not enough that it can't be compensated for. There have been many incidents of engines falling off for various reasons. All but a couple have landed safely. The times that it caused a crash it was due to other systems damaged because they didn't separate as they were intended to.

Who isn't fan of Donnie Darko ? :)

Any time the question is "why don't we have...", the answer is almost certainly in the trade-off between weight, maintenance cost, fuel cost, & utility. If it weighs a lot, needs maintenance, burns fuel, and will only be useful once a decade, then it just is not productive.
Putting an engine release system on a plane will be heavy, meaning fewer passengers, or less fuel or cargo on board. All that extra weight has to be flown around, requiring fuel. The release mechanism would need regular maintenance checks, which is another cost. And it would only be useful very, very infrequently (on most planes, it would never be used).
So it is just impossible to justify adding new equipment for a once-in-a-lifetime scenario, which can be better managed with good maintenance, good training, and good planning.
This same line of reasoning goes for "why don't more airplanes have rocket thrusters?", "why don't planes have anti-missile systems?", "why don't planes have airbags?", "Why don't airplanes have parachutes?" and many other random items.

I think the real reason is dropping, effectively, a bomb from an airplane over even a slightly dense population is likely to cause as much damage and loss of life as-if everyone on the plane died in a crash. Given it's far more unlikely for an engine fire to crash an airplane, that's not really an acceptable risk.

@SnakeDoc:  The world is a lot more empty than you may realize.  70% of the earth is water, and upwards of 95% of land has no one on it at all.  Without even trying, you could drop an engine at any time, and probably not do any damage at all.

@abelenky That's going to depend where you're flying. http://i.dailymail.co.uk/i/pix/2014/04/18/article-2607431-1D2B229B00000578-883_964x585.jpg In the USA midwest, you're probably right, but most places over the east coast... not so much. I still think dropping hunks of metal from airplanes at random is more of a problem for the general population than if all passengers died. Sounds blunt, but the likelihood of the airplane falling from the sky is so small, that it makes dropping engines more of a risk than simply extinguishing the fire or landing with it on fire.

@abelenky We like to put airports near population centers (KJFK, KLGA, KLAX, KORD, KATL…), and coastal waters can have quite a few ships (pleasure, merchant, and military) sailing around in them: Even if the detachment process could be made simple and lightweight (explosive bolts and the existing mechanisms that clamp fuel/oil/hudraulic/pneumatic lines to a severed pylon) along the lines of military aircraft with drop-tanks for fuel it would never pass the safety-of-people-on-the-ground test for civil aircraft.

With a release mechanism, the risk of accidentally dropping an engine is probably similar to the risk of a fire in the engine.

Ahh - a voice of reason! +1.

@SnakeDoc's answer is statistically and realistically correct.  Ever since the advent of "Sputnik" all kinds of unusual objects have fallen out of the sky above our heads; they haven't hurt Earth's human population, nor permanently scarred Mother Earths' surface, either.  But now Airbus has started planning, and building, a triple-decker passenger jet that can carry more than 700 passengers.  With the "Titanic" in mind, I believe that provision for life-saving engine-jettisoning in emergencies will absolutely be an aircraft design requirement in near-future ICAO and FAA regulations.

Why don't planes have anti-missile systems? They do. Why don't planes have airbags? They do. Why don't airplanes have parachutes? They do. So I wouldn't say "impossible." There are quite a few safety systems on aircraft that rarely get used.

I think the "uncontrolled bomb" answer is probably sufficient on its own but there are also technical reasons.
In order to be able to drop the engine you need to build the engine with a rapid release system that will safely, reliably and near-instantly disconnect the engine and all the wires and fuel lines connected to the engine. What's more it needs to be able to do this while it is on fire following an emergency failure that caused the fire. It is not obvious that this is actually possible, but even assuming it is you are adding a new complex system to the engine assembly that is, itself, capable of failure and where failure has potentially disastrous consequences.
Thus its possible, likely even, that adding an "engine eject" module to a plane is likely to increase the overall risk to the plane rather than decreasing it.

authors: К. Келлогг Смиф


text:
What is the process of obtaining a commercial license after revocation?
I held a 2nd class medical and a commercial pilot license. My certificates were revoked due to an alleged DUI which I didn't get convicted of. I have been trying to contact every division in the FAA just to speak with someone about the process of getting my certificates back, however, due to COVID-19 not a soul is in the office nor, apparently, returning phone calls. Any ideas on which direction to go to obtain my certificates? Or possibly a direct number to someone to speak with about the matter?

Have they actually revoked the certs, or just threatened action? There should have been several letters, with details on what information they wanted, when to respond, your rights, etc. Also, are you sure it is both certs? A DWI is normally only disqualifying for the medical cert, not the pilot cert.

If your pilot's certificate was definitely revoked then it's gone for good. You'll have to reapply and re-qualify for all your certificates and ratings again, although you have to wait a year first per 14 CFR 61.13(d)(2):

Unless otherwise authorized by the Administrator, a person whose
pilot, flight instructor, or ground instructor certificate has been
revoked may not apply for any certificate, rating, or authorization
for 1 year after the date of revocation.

Certificate revocation is the FAA's 'nuclear option' and they don't do it lightly. Your best option here is to contact AOPA (if you're a member) and/or an aviation lawyer for specific advice.